Patterned array of uniform metal microbeads

Abstract

The present invention provides a method for providing an array of metal microbeads on a substrate, preferably in a regular pattern of very fine, uniform size microspheres or microbeads at precise spacing or scale previously unachievable. The method of the present invention comprises the steps of providing a metal layer on a substrate that is partitioned into metal regions; heating the metal layer to a temperature sufficient to melt the metal and to permit beading of the layer into discrete microbeads.

What is claimed is: 
     
       1. A method of providing an array of microspheres on a substrate, comprising the steps of: a) providing a metal layer on a substrate, said metal layer sufficiently partitioned into a plurality of metal regions to permit beading of the metal regions;   b) heating said metal layer to a temperature sufficient to melt the metal regions and o permit beading of the metal regions into discrete microspheres, thereby providing an array of discrete microspheres on a substrate.   
     
     
       2. The method of claim 1 wherein the metal regions are provided by depositing said metal layer on said substrate followed by a step wherein said metal layer is partitioned into metal regions. 
     
     
       3. The method of claim 1 wherein said metal layer is deposited onto said substrate so as to be sufficiently partitioned into metal regions as deposited. 
     
     
       4. The method of claim 1 wherein said metal regions are defined by a first set of parallel grooves intersecting a second set of parallel grooves, such that said metal regions are parallelograms. 
     
     
       5. The metal of claim 1 wherein said metal regions have three sides. 
     
     
       6. The method of claim 1 wherein said metal layer has a thickness of about 0.2-10 μm. 
     
     
       7. The method of claim 6 wherein said metal layer has a thickness of about 0.2-2 μm. 
     
     
       8. The method of claim 1 further including the step of contacting said layer with an effective amount of a fluxing agent sufficient to permit beading of said metal regions. 
     
     
       9. The method of claim 1 wherein said microspheres are formed having an average density of about 600-6,000,000 beads/cm 2 . 
     
     
       10. The method of claim 9 wherein said metal microspheres have an average density of about 40,000-6,000,000 beads/cm 2 . 
     
     
       11. The method of claim 10 wherein said metal microspheres have an average density of about 80,000-6,000,000 beads/cm 2 . 
     
     
       12. The method of claim 1 wherein said array of metal microspheres is a regular array. 
     
     
       13. The method of claim 1 wherein said metal regions are all of a single uniform surface area, thereby forming a regular array of microbeads of a single size. 
     
     
       14. The method of claim 1 wherein said metal regions have 2 or more uniform sizes. 
     
     
       15. The method of claim 1 wherein the diameter of said microspheres is about 0.2-100 μm. 
     
     
       16. The method of claim 15 wherein the diameter of said microspheres is about 1-50 μm. 
     
     
       17. The method of claim 1 further including a step of transferring said array of metal microspheres to a second substrate. 
     
     
       18. The method of claim 17 further including an adhesive layer on said second substrate with said array of metal microspheres transferred into said adhesive layer.